Posing as a woman and offering free tattoos, an man lured teens to secluded spots in Allentown.

A 20-year-old Allentown man who posed as a female tattoo artist online to lure teens to secluded areas around the city, where he sexually and physically assaulted them, faces up to 30 years in state prison.

Unique Santiago of Chew Street will also be a registered sex offender for the rest of his life. He pleaded guilty Tuesday before Lehigh County Judge Kelly Banach to two counts of sexual assault and one count of aggravated assault.

Santiago admitted to attacking three teenage girls, and sexually assaulting two of them. One girl was able to get away after being punched in the face with brass knuckles.

According to court records:

On Feb. 28, 2012, Santiago posed as "Erica Wave," a female tattoo artist, on Facebook and struck up an online conversation with a 14-year-old girl. The girl wanted a tattoo, prosecutors said, but did not have her parents' permission.

"Erica" offered to give the girl a free tattoo, and arranged to meet her at the West End Cemetery around 10 p.m. When the girl arrived at the meeting spot, a man in a black ski mask knocked her to the ground, told her he had a knife, and raped her.

The rapist fled on foot after the assault. The girl told police that she was walking home from the cemetery and she ran into Santiago, whom she knew through mutual friends. She told him she'd been raped and he acted upset, then walked her home.

The next attack occurred on June 30, 2013, court records say. An 18-year-old woman received a text message from an "Angelica," whom she believed to be a friend of a friend. "Angelica" asked to meet the girl at a home where she was baby sitting, and the woman gave the texter the address.

A man wearing a black ski mask soon arrived at the home and punched the girl with brass knuckles. He tried to drag her to a secluded area near the house but she got away.

On Oct. 2, 2013, court records say, a 19-year-old woman was contacted via Facebook by tattoo artist "Erica Wave," and they had a lengthy online conversation. "Erica" persuaded the woman to meet her near 11th and Washington streets.

When the victim arrived, a man dragged her into an alleyway and raped her.

Police traced the "Erica Wave" Facebook account to a computer at Santiago's home. Tests later showed that his DNA was found on both sex assault victims.

Court records say he confessed to police and admitted that a pair of brass knuckles found at his home were used in the attacks. Court records show that police also recovered Facebook photos of Santiago posing with the weapons.

Santiago did not testify during the hearing Tuesday. As part of a plea agreement, prosecutors dropped rape charges.

Chief Deputy District Attorney Matthew Falk said that he spoke to all three victims and that they agreed with the plea deal.

"Frankly, given the choice, the victims would rather not testify," he told Banach.

Santiago's attorney, Glennis Clark, declined to comment after the hearing.

Santiago will be sentenced in March and remains behind bars under $80,000 bail. He will undergo evaluation to determine if he fits the legal criteria to be labeled a sexually violent predator. If that occurs, Santiago's neighbors will be notified when he's released from prison and moves into a community.